Fully enclosed, adjustable, support column for a pivotal chair

ABSTRACT

A support column for a pivotal chair. The support column may be fully enclosed and yet permit selective adjustability in the height of the seat section above a base portion merely by rotation of the seat section. A threaded spindle is nonrotatably secured to, and extends downwardly from, a seat section and is received within a hub tube that extends upwardly from the base portion. An adjusting nut is threaded onto the spindle to control the axial extent to which the spindle is received within the hub tube and thereby regulates the height of the seat section above the base portion. The adjusting nut is normally rotatable with the spindle, and an arm is secured to the adjusting nut which will engage a lost motion device after the seat section has been rotated through no more than a predetermined angular range. After the seat section has been further rotated through no more than an additionally predetermined angular range, the lost motion device - which is mounted to be freely rotatable with respect to the spindle - contacts a stop so that continued rotation of the seat section in the same direction effects relative movement between the spindle and the adjusting nut to adjust the height of the seat section. The angular range through which the seat section is rotated before the stop restrains both the lost motion device and the arm on the adjusting nut from rotating with the spindle constitutes the free pivotal range through which the seat section can be rotated without effecting any adjustment in the height thereof.

United States Patent [191 I Holtz 1 Mar. 11, 1975 1 FULLY ENCLOSED, ADJUSTABLE,

SUPPORT COLUMN FOR A PIVOTAL CHAIR [75] Inventor: Richard L. Holtz, Sturgis, Mich.

[73] Assignee: Harter Corporation, Sturgis, Mich.

[221 Filed: Oct. 31, 1973 211 App]. No.: 411,197

[52] US. Cl. 248/406, 297/349 [51] Int. Cl. F16m 11/24 [58] Field of Search 248/405, 406, 404, 161, 248/188.7, 188.4; 297/349; 108/147 [56] References Cited UNITED STATES PATENTS 2,704,113 3/1955 McKinley 248/406 3,164,357 1/1965 Hage et a1.... 248/406 3,227,113 l/l966 Kupski 248/161 X 3,386,697 6/1968 Helms 248/406 3,439,893 4/1969 Paquette... 248/405 3,642,244 2/1972 Textoris.... 248/406 3,727,871 4/1973 Harper 248/406 3,778,014 12/1973 Driscol et al. 248/406 3,799,486 3/1974 Mohr et a1. 248/406.

Primary ExaminerJames T. McCall Arlorney, Agent, or FirmHamilton, Renner & Kenner 571 ABSTRACT A support column fora pivotal chair. The support column may be fully enclosed and yet permit selective adjustability in the height of the seat section above a base portion merely by rotation of the seat section. A threaded spindle is nonrotatably secured to, and extends downwardly from, a seat section and is received within a hub tube that extends upwardly from the base portion. An adjusting nut is threaded onto the spindle to control the axial extent to which the spindle is received within the hub tube and thereby regulates the height of the seat section above the base portion. The adjusting nut is normally rotatable with the spindle, and an arm is secured to the adjusting nut which will engage a lost motion device after the seat section has been rotated through no more than a predetermined angular range. After the seat section has been further rotated through no more than an additionally predetermined angular range, the lost motion device which is mounted to be freely rotatable with respect to the spindle contacts a stop so that continued rotation of the seat section in the same direction effects relative movement between the spindle and the adjusting nut to adjust the height of the seat section. The an-- gular range through which the seat section is rotated before the stop restrains both the lost motion device and the arm on the adjusting nut from rotating with the spindle. constitutes the free pivotal range through which the seat section can be rotated without effecting any adjustment in the height thereof.

13 Claims, 10 Drawing Figures FULLY ENCLOSED, ADJUSTABLE, SUPPORT COLUMN FOR A PIVOTAL CHAIR BACKGROUND OF THE INVENTION The present invention relates generally to an adjustable support column for pivotally mounting the seat section of a chair to a base portion.

Historically, adjustment in the height of a seat has been accomplished by the use of a threaded spindle that becomes progressively exposed as the seat is raised by threading the spindle upwardly out of a bell nut and hub tube.

In response to considerations of: improving the operating efficiency (by shielding the threaded portion of the spindle from deleterious dust and dirt); providing an aesthetically improved appearance (by shielding the threaded spindle from view); and, maintaining cleanliness (by shielding the person using the chair, and his or her clothes, from the lubricant employed on the threaded spindle), various types of cover assemblies and concommitant mechanisms for permitting selective height adjustability have been provided. However, the prior known configurations have not been totally ac-' ceptable.

One approach has necessitated the incorporation of a special connection between the seat section of the chair and the threaded spindle often by inserting a pivot therebetween in order to permit the seat section to be rotated without effecting an adjustment in the height of the seat.

Another approach has necessitated some physical connection between the cover assembly and the adjusting mechanism hidden thereby. But irrespective of the approach, the ability to raise and lower a pivotally mounted seat section simply by the convenient expedient of rotating the seat section has not heretofore been accomplished, and on the basis of the state to which the prior art has advanced, to provide such a result in conjunction with a cover arrangement has been considered well nigh impossible.

SUMMARY OF THE INVENTION It is, therefore, a primary object of the present invention to provide a support column for pivotally mounting the seat section of a chair to a base, said support column affording height adjustability by rotation of the seat section with respect to the base portion.

It is another object of the present invention to provide a support column for a chair, as above, which permits the seat section to rotate through a free pivotal range of approximately one and three-fourths revolutions without effecting any adjustment in the height thereof.

It is a further object of the present invention to provide a column for a chair, as above, which affords adjustability in the height of the seat section by rotation thereof beyond the one and three-fourths revolutions provided for the free pivotal range.

These and other objects, together with the advantages thereof over existing and prior art forms which will become apparent from the following specification, are accomplished by means hereinafter described and claimed.

In general, an adjustable support column embodying the concept of the present invention incorporates a hub tube that extends upwardly from a base portion to receive at least a portion of a threaded spindle that is fixedly secured to, and extends downwardly from, a seat section. The portion of the spindle received within the hub tube may rotate and/or reciprocate with respect thereto, and an adjusting nut assembly is threaded onto the spindle to establish theextent to which the spindle can be inserted into the hub tube and thereby adjust the height of the seat section relative to the base portion.

A first arm means presented from the adjusting nut is indirectly engeagable with a stop presented from the hub tube. In fact, the indirect engagement may be affected by a lost motion device comprising a second arm means that is mounted for free rotation on the spindle said second arm means being engageable by the first arm means upon no more than a predetermined degree of rotation by said seat section, and the second arm means, in turn, engaging the stop upon no more than an additional, predetermined degree of rotation by said seat section.

As such, the height of the seat section can be adjusted by rotation of the seat section, but only after the seat section has rotated through a given range of free pivotal movement.

A telescoping cover arrangement may extend between the seat section and the base portion to enclose the spindle, hub tube, adjusting nut and interconnecting mechanism.

One preferred embodiment of an adjusting support column for a pivotally mounted chair embodying the concept of the present invention is shown by way of example in the accompanying drawings without attempting to show all of the various forms and modifications in which the invention might be embodied; the invention being measured by the appended claims and not by the details of the specification.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a frontal-side perspective of a chair embodying the concept of the present invention, the seat section of the chair being exploded upwardly to reveal the uniquely adjustable support column extending upwardly from the base portion and being, in part, broken away to conserve space;

FIG. 2 is an enlarged, exploded, perspective of a portion of the internal mechanism incorporated in the adjustable support column depicted in FIG. 1;

FIG. 3 is an enlarged vertical section taken substantially along line 3-3 of FIG. 1 and depicting the mechanism interiorly of the support column, said mechanisms being disposed to permit a range of free pivotal movement to the seat section without effecting an adjustment in the height thereof;

FIG. 4 is a horizontal section taken substantially along line 4-4 of FIG. 3 and appearing on the same sheet of drawings as FIGS. 1 and 2;

FIG. 5 is a further horizontal section taken substantially along line 55 of FIG. 3 and appearing on the same sheet of drawings as FIG. 3;

FIG. 6 is a still further horizontal section taken substantially along line 6-6 of FIG. 3 and appearing on the samesheet of drawings. as FIGS. 3 and 5;

FIG. 7 is a still further horizontal section taken substantially along line 7-7 of FIG. 3;

FIG. 7a is a view similar to FIG. 7 but depicting the mechanism disposed to permit vertically upward adjustment in the height of the seat section above the base portion;

FIG. 8 is an even further horizontal section taken substantially along line 8-8 of FIG. 3; and,

FIG. 9 is a vertical section similar to FIG. 3 but depicting the mechanism interiorly of the support column disposed to permit vertically upward adjustment in the height of the seat section above the base portion.

DESCRIPTION OF A PREFERRED EMBODIMENT A support column embodying the concept of the present invention is designated generally by the numeral 10 in the appended drawings and is depicted as providing adjustment in the height of a seat section 11 above a base portion 12 in a chair 13.

The base portion 12 may comprise a plurality of legs 14 that are conjoined at the nave 15 to support a hub tube 16 that is secured to, and extends vertically upwardly from, the nave 15. An annular bushing, or liner, 18 is received within the hub tube 16 and a nib 19 (FIG. 3) on the outer surface thereof may be positioned within a radial bore 20 in the hub tube 16 to anchor the bushing 18 therein. The bushing 18 is preferably made of a plastic such as Zytel to provide a selflubricating, bearing surface for a spindle 22 that is secured to, and extends vertically downwardly from, the seat section 11. The spindle 22 is secured to rotate with the seat section 11, and this result may be effected by staking, press fitting or otherwise securing the point 23 of the spindle 22 within a chair control 24 fastened to the underside of the seat section 11. The threaded portion 25 of the spindle 22 is rotatably and reciprocatingly received within the bushing 18.

A flange 26 extends radially outwardly from the upper extremity in the bushing 18 and engages the upper rim 28 of the hub tube 16.

An adjusting nut 30 is threaded onto the threaded portion 25 of spindle 22 and presents a first arm means 31 that is, upon rotation through a predetermined range, engageable with a lost motion device 32 which, upon movement to a further predetermined range, is engageable with a stop 33 presented from the hub tube 16.

Although the foregoing arrangement can be accomplished in a number of ways, the embodiment depicted works quite well, and in that construction the arm means 31 is secured to the nut 30 and extends downwardly therefrom in generally parallel, radially outwardly spaced, relation to the spindle 22.

The lost motion device 32 may well comprise a washer 34 that is mounted for free rotation on the spindle 22 medially and adjusting nut 30 and hub tube 16. As best seen in FIGS. 3 and 9 the washer 34 is sandwiched between the flange 26 on bushing 18 and a J- washer 35, the purpose for which will be more fully hereinafter described.

A second arm means 36 is secured to, and extends downwardly from, the washer 34 in generally parallel,

radially outwardly spaced, relation to the spindle 22.

The first and second arm means 31 and 36, respectively, are disposed to interengage upon a predetermined degree of angular movement. At .least the second arm means 36 may be disposed to extend downwardly past the outer surface 3.8 of the hub tube 16 in radially outwardly spaced relation with respect thereto in order to engage the stop 33 which projects radially outwardly beyond the outer surface 38 of the hub tube 16.

In the embodiment depicted, the stop 33 is represented as being a bar-like arrangement secured to the outer surface 38 of the hub tube 16, but the stop 33 could just as well be a projecting pin received within a bore in the hub tube 16, or, for that matter, an extension of the nib 19 on bushing 18 which would extend outwardly through the radial bore 20 in the hub tube 16. Thus, it should be apparent that any number of configurations would satisfy the purpose of the present invention.

In order to adjust the height of the seat section, the arm means 31 must engage arm means 36 and the arm means 36 must engage stop 33, both in the direction the seat section is being rotated (depending upon whether the seat section is to be raised or lowered). As shown in FIGS. 7a and 9, one lateral edge 39 on arm means 31 engages the opposed lateral edge 40 of arm means 36, and the opposite edge 41 of arm means 36 engages one side 42 of stop 33. With the arm means 31 and 36 as well as the stop 33 so juxtaposed, continued counter-clockwise rotation of the seat section 11 (as viewed from above) will cause the spindle 22 to turn upwardly out of the adjusting nut 30 and thereby raise the seat section 11.

Should one elect to rotate the seat section 11 in a clockwise direction (also as viewed from above) there would be nothing restraining the free movement of arm means 31, and the nut 30 would simply rotate with the spindle 22. This restraining result is assured by the use of the J-washer, or other suitable retarding means, 35. Specifically, a radially inwardly directed key 46 on J- washer 35 engages an axial slot 48 in the threaded portion 25 of spindle 22 so that the J-washer 35 will rotate with, but not with respect to, the spindle 22. At least one flat surface 49 on the J-washer 35 is provided with a plurality of radially extending ridges, or other comparable protuberances, 50 that engage with grooves, or recesses, 51 in the juxtaposed under surface 52 of nut 30 to urge the nut 30 to rotate with the spindle 22.

After approximately 320 counter-clockwise rotation of the seat section 11 from the FIG. 9 position, the opposite lateral edge 53 on arm means 31 would engage edge 41 of arm means 36. Because the washer 34 is free to rotate about spindle 22, continued clockwise rotation of seat section 11 with the edges 53 and 41 of arm means3l and 36, respectively, engaged, rotates the lost motion device 32 with the nut 30. After approximately 320 further clockwise rotation of the seat section the lateral edge 40 of arm means 36 will engage the opposite side 54 of stop 33.

Continued clockwise rotation of seat section 11 with I the arm means 31 and 36 as well as the stop 33 so juxtaposed will cause the spindle 22 to be screwed downwardly into the adjusting nut 30, thereby lowering the seat section 11. However, the approximately 640, or one and three-quarters revolutions, range of rotation between the juxtapositioning of the stop 33 and arm means 31 and 36 to effect either a raising or lowering of the seat section comprises the free pivotal range afforded to the seat section 11 supported by a column embodying the concept of the present invention.

It must be appreciated that when the adjusting nut 30 is restrained from rotation by engagement of the juxtaposed arm means 31 and 36 with the stop.33, the ridges 50 on J-washer 35 will slip across the grooves 51 on the nut 30 to permit rotation of the spindle 22 with respect to the adjusting nut 30.

As such, the hub tube 16, spindle 22, adjusting nut 30 and the mechanism interconnecting the adjusting nut 30 with the hub tube 16 may be completely inaccessible without impairing the adjustability in the height of the seat section 11 above the base portion 12, and a suitable cover 55 may be employed to conceal those parts.

In the embodiment depicted, an outer hub cover 56 may be positioned in concentrically spaced relation about the hub tube 16. This disposition of the outer hub cover 56 is achieved by the cooperative effect of a spacer 58 which circumscribes the hub tube 16 in proximity to the nave l5, and the crenelated lower edge of the outer hub cover 56. As best seen in FIGS. 3 and 9, the tines 59 forming the crenelations conform to the legs 14 and present decorative fillets therebetween.

The inner hub cover 60 is suspended from the seat section 11 and is telescopically received within the outer hub cover 56. One may conveniently suspend the inner hub cover 60 by means of an annular ring 61 that rests on the shoulder 62 formed at the juncture of the threaded portion 25 and the point 23 of the spindle 22. The ring 61 may be secured to the interior surface 63 of the inner hub cover 60, the upper edge 64 of which engages the under surface 65 of the chair control 24 on the seat section 11.

In order to preclude inadvertent separation of the seat section 11 from the base portion 12, as by lifting the seat section 11 in an attempt to lift the entire chair 13, a releasable interconnect is preferably provided. The interconnect may comprise a screw 68 that is threadably received within a bore 69 through the first arm means 31. With the screw 68 removed, the arm means 31 may be readily translated past the flange 26 on bushing 18 to allow the seat section 11 to be lifted independently of the base portion 12 and thereby to be physically separated from the base portion, but with the screw 68 extending radially inwardlyof the arm means 31 in its operative position it will engage the flange 26, thereby serving to preclude separation of the seat from the base. It should be appreciated that when a cover arrangement 55 is employed an access bore 70 should be provided through the appropriate hub cover (the inner hub cover 60 as depicted in FIG. 3) to permit access to the screw 68 in order that the chair 13 may be selectively assembled and disassembled.

It should thus be apparent that a chair embodying the concept of the present invention: permits the height of the seat section to be adjusted merely by rotation of the seat section with respect to the base portion; allows the seat section to be pivotal through a predetermined angular range with respect to the base portion without changing the height of the seat section; and, otherwise accomplishes the objects of the invention.

I claim:

1. An adjustable support column for pivotally mounting the seat section of a chair to a base portion comprising: a hub tube extending upwardly from the base, a threaded spindle non-rotatably secured to, and extending downwardly from, the seat section, at least a portion of said threaded spindle being rotatably and reciprocatingly received within said hub tube, an adjusting nut threaded onto said spindle to establish the extent to which said spindle can extend within said hub tube and thereby control the height of the seat section, a stop presented from said hub tube, a first arm means secured to said adjusting nut, and a lost motion device interposed between said arm and said first stop to permit relative rotation of said spindle with respect to said adjusting nut in order to effect adjustment in the height of said seat section only after the seat section has rotated within a range of free pivotal movement in either direction, the total range of such free pivotal movement being at least one full revolution.

2. An adjustable support column, as set forth in claim 1, in which said lost motion device comprises a second arm means mounted to rotate about said spindle, said second arm means being engageable by said first arm means and said stop being sequentially engageable by said second arm means upon rotation of the seat section beyond a predetermined free pivotal range.

3. An adjustable support column, as set forth in claim 2, in which said first arm means is rotatable through a range of up to approximately 320 before engaging said second arm means, and said second arm means being rotatable through a range of up to approximately 320 before engaging said stop.

4. An adjustable support column, as set forth in claim 3, in which retarding means are operatively interposed between said spindle and said adjusting nut.

5. An adjustable support column, as set forth in claim 4, in which a first cover tube surrounds said hub tube and extends upwardly from the base portion, and in which a second cover tube surrounds said spindle and extends downwardly from the seat section, said first and second cover tubes being telescopically interfitted.

6. An adjustable support column, as set forth in claim 5, in which the retarding means comprises a J-washer non-rotatably mounted from said spindle, said J-washer being located in juxtaposition with said adjusting nut, first means on said J-washer interacting with second means on said adjusting nut to retard relative rotation therebetween. I

7. A chair having an adjustable support column comprising; a seat section, a base portion, a hub tube secured to and extending upwardly from said base portion, a threaded spindle, means non-rotatably to con- -nect said threaded spindle to said seat section, an adjusting nut threaded onto said spindle to establish the height of said seat section above said base portion, a stop presented from said hub tube, a first arm means presented from said adjusting nut, and a lost motion device interposed between said stop and said first arm means.

8. A chair, as set forth in claim 7, in which said lost motion device comprises a second arm means mounted to rotate about said spindle, said second arm means being engageable by said first arm means and said stop being sequentially engageable by said second arm means upon rotation of the seat section beyond a predetermined free pivotal range.

9. A chair, as set forth in claim 8, in which said first arm means is rotatable through a range of up to approximately 320 before engaging said second arm means, and said second arm means being rotatable through a range of up to approximately 320' before engaging said stop.

10. A chair, as set forth in claim 9, in which retarding means are operatively interposed between said spindle and said adjusting nut.

11. A chair, as set forth in claim 10, in which a first cover tube surrounds said hub tube and extends upwardly from the base portion, and in which a second cover tube surrounds said spindle and extends downsaid interconnect means in order to permit assembly and disassembly of said seat section with respect to said base portion.

13. A chair, as set forth in claim 12, in which said in terconnect means comprises a screw threadably received through at least one said arm means and in which a bore is provided through at least one said cover tube to permit access to said screw. 

1. An adjustable support column for pivotally mounting the seat section of a chair to a base portion comprising: a hub tube extending upwardly from the base, a threaded spindle nonrotatably secured to, and extending downwardly from, the seat section, at least a portion of said threaded spindle being rotatably and reciprocatingly received within said hub tube, an adjusting nut threaded onto said spindle to establish the extent to which said spindle can extend within said hub tube and thereby control the height of the seat section, a stop presented from said hub tube, a first arm means secured to said adjusting nut, and a lost motion device interposed between said arm and said first stop to permit relative rotation of said spindle with respect to said adjusting nut in order to effect adjustment in the height of said seat section only after the seat section has rotated within a range of free pivotal movement in either direction, the total range of such free pivotal movement being at least one full revolution.
 1. An adjustable support column for pivotally mounting the seat section of a chair to a base portion comprising: a hub tube extending upwardly from the base, a threaded spindle non-rotatably secured to, and extending downwardly from, the seat section, at least a portion of said threaded spindle being rotatably and reciprocatingly received within said hub tube, an adjusting nut threaded onto said spindle to establish the extent to which said spindle can extend within said hub tube and thereby control the height of the seat section, a stop presented from said hub tube, a first arm means secured to said adjusting nut, and a lost motion device interposed between said arm and said first stop to permit relative rotation of said spindle with respect to said adjusting nut in order to effect adjustment in the height of said seat section only after the seat section has rotated within a range of free pivotal movement in either direction, the total range of such free pivotal movement being at least one full revolution.
 2. An adjustable support column, as set forth in claim 1, in which said lost motion device comprises a second arm means mounted to rotate about said spindle, said second arm means being engageable by said first arm means and said stop being sequentially engageable by said second arm means upon rotation of the seat section beyond a predetermined free pivotal range.
 3. An adjustable support column, as set forth in claim 2, in which said first arm means is rotatable through a range of up to approximately 320* before engaging said second arm means, and said second arm means being rotatable through a range of up to approximately 320* before engaging said stop.
 4. An adjustable support column, as set forth in claim 3, in which retarding means are oPeratively interposed between said spindle and said adjusting nut.
 5. An adjustable support column, as set forth in claim 4, in which a first cover tube surrounds said hub tube and extends upwardly from the base portion, and in which a second cover tube surrounds said spindle and extends downwardly from the seat section, said first and second cover tubes being telescopically interfitted.
 6. An adjustable support column, as set forth in claim 5, in which the retarding means comprises a J-washer non-rotatably mounted from said spindle, said J-washer being located in juxtaposition with said adjusting nut, first means on said J-washer interacting with second means on said adjusting nut to retard relative rotation therebetween.
 7. A chair having an adjustable support column comprising; a seat section, a base portion, a hub tube secured to and extending upwardly from said base portion, a threaded spindle, means non-rotatably to connect said threaded spindle to said seat section, an adjusting nut threaded onto said spindle to establish the height of said seat section above said base portion, a stop presented from said hub tube, a first arm means presented from said adjusting nut, and a lost motion device interposed between said stop and said first arm means.
 8. A chair, as set forth in claim 7, in which said lost motion device comprises a second arm means mounted to rotate about said spindle, said second arm means being engageable by said first arm means and said stop being sequentially engageable by said second arm means upon rotation of the seat section beyond a predetermined free pivotal range.
 9. A chair, as set forth in claim 8, in which said first arm means is rotatable through a range of up to approximately 320* before engaging said second arm means, and said second arm means being rotatable through a range of up to approximately 320* before engaging said stop.
 10. A chair, as set forth in claim 9, in which retarding means are operatively interposed between said spindle and said adjusting nut.
 11. A chair, as set forth in claim 10, in which a first cover tube surrounds said hub tube and extends upwardly from the base portion, and in which a second cover tube surrounds said spindle and extends downwardly from the seat section, said first and second cover tubes being telescopically interfitted.
 12. A chair, as set forth in claim 10, in which an interconnect means extends radially inwardly of at least one said arm means, an annular flange being attached to, and extending outwardly of, said hub tube, said flange being positioned upwardly of said interconnect means to preclude inadvertent separation of the seat section from said base portion, and means radially to withdraw said interconnect means in order to permit assembly and disassembly of said seat section with respect to said base portion. 